the morning after pill is not meant as a form of birth control it is meant to be used if something like a comdom breaks you can use it as a back up or you can use it in rape cases....but you cna have your period and still be pregnant my mother had periods he whole pregnancy with me but I'm hear so that doesn't mean anything. And the best way to be sure not to get pregnant is NO SEX or be responsible and use birth control pill and or condoms......but always use condoms so you don't get an STD......
If you have a normal period after unprotected sex, ie a period that fills sanitary towels or tampons then I think its safe to assume that you are most likely NOT pregnant, although this is not guaranteed, any unprotected sex carries risk of pregnancy.
The morning after pill is most effective for the 24 hour period after you have had sex, 36 hours its around 85% effective and so on.
Pulling out or withdrawal is not effective at all as a means of contraceptive, why not take the pill?